This invention relates to a method and apparatus for the rapid quantitative determination of .alpha.-amylase in any fluid which contains .alpha.-amylase, particularly in biologic fluids such as blood serum and urine, or any other fluid containing .alpha.-amylase and glucose.
Serum amylase is generally regarded as the single most important practical diagnostic test in cases of acute pancreatitis. Procedures for the rapid measurement of .alpha.-amylase activity in blood serum have been proposed, and would be desirable wherein a short time is available or required for obtaining the value of the measurement in emergency situations.
Various rapid procedures are disclosed in the patent art for use in determining and monitoring various components in serum solutions, particularly for glucose, urea, etc., e.g. U.S. Pat. Nos. 3,367,849; 3,421,982; 3,512,517; 3,591,480; 3,838,011; 3,926,734; 3,947,328; and others.
With respect to the determination of .alpha.-amylase in serum or other body fluids, the following is a list of presently known literature references on the matter:
1. Caraway, W. T., "A Stable Starch Substrate for the Determination of Amylase in Serum and other Body Fluids." Amer. J. Clin. Pathol. 32, 97 (1959).
2. Somogyi, M., "Micro Methods for the Estimation of Blood Diastase." J. Biol. Chem. 125, 399 (1938).
3. Peralta, O., and Reinhold, J.G., "Rapid Estimation of Amylase Activity of Serum by Turbidimetry." Clin. Chem. 1, 157 (1955).
4. Sax, S. M., Bridgewater, A. B., Moore, J. J., "Determination of Serum and Urine Amylase with Use of Procion Brilliant Red M-2BS Amylopectin." Clin. Chem. 17, 311 (1971).
5. Chung, K. Y., Sinha, R. M., and Trew, J. A., "Comparison of Two Methods For Determining Amylase Activity in Serum and Urine." Clin. Chem. 17, 89 (1971).
6. Ceska, M., Birath, K., and Brown, B., "A New and Rapid Method for the Clinical Determination of .alpha.-Amylase Activities in Human Serum and Urine. Optimal Conditions." Clin. Chem. ACTA, 26, 437 (1969).
7. Henry, R. J., and Chiamori, N., "Study of the Saccharogenic Method for the Determination of Serum and Urine Amylase." Clin. Chem. 6, 434 (1960).
8. Shipe, J. R., and Savory, J., "Kinetic Nephelometric Procedure For Measurement of Amylase Activity in Serum." Clin. Chem. 18, 1323 (1972).
9. Zinterhofer, L., Wardlaw, S., Jatlow, P., and Seligson, D., "Nepheolometric Determination of Pancreatic Enzymes. I. Amylase" Clin. Chem. Acta, 43, 5 (1973).
10. Smeaton, J. R. and Marquart, W. F., "A Reaction Rate Nephelometer for Amylase/Lipase Determinations." Clin. Chem. 20, 896 (1974) Abstract.
11. Smith, B., and Roe, J. H., "A Photometric Method for the Determination of .alpha.-Amylase in Blood and Urine With Use of Starch-Iodine Color", J. Biol. Chem. 179, 53 (1949).
12. J. John Marshall et al, "A New Serum .alpha.-Amylase Assay of High Sensitivity", Clin. Chem. Acta, 76, 277, (1977).
Most of the methods commercially used for the measurement of alpha-amylase activity use a starch substrate and either measure reducing reaction products which are sugars, or measure the amount of starch hydrolyzed as the reaction progresses. The measurement of the starch substrate is accomplished both chemically and physically by iodometric, turbidimetric, viscosimetric, and dye-complexing methods.
An instrument presently available for measuring the .alpha.-amylase activity uses a kinetic, turbidimetric method for the determination of .alpha.-amylase activity and uses an insoluble amylopectin substrate with activity determined by the rate of decrease in turbidity.
Although the above procedures have been found satisfactory, it has been a desideratum of persons in the medical field conducting tests for .alpha.-amylase in various solutions to have for use a procedure which, among other things, is rapid in its quantitative determination of the .alpha.-amylase content, and has ease of operation.